Send an email to this guy, snyiri at mantrackenya dot com

Will they use the generator for everything or just the lights? If everything (cooking, hot water, ironing etc), you will need a serious plant. If just lights, you will need to rewire the place to enable only the line fed by the generator to run the lights. @mgeman, I believe mantrac are the former Gaily&Roberts???

If its a middle class area, assume each apartment has fridge, a TV, a microwave and that each apartment has two bedroom and instant hot shower it is 2KVA per apartment. It adds to 25KVA assuming diversity factor of 35% expansion factor of 0%

You will need it to come with Automatic change over switch (or have the caretaker to manually start and stop which is cumbersome)

Another thing, you will need to sensitize the residents that cooking with electricity when the apartment block is on Generator is not allowed otherwise it will trip during peak periods (7pm-9:30pm)

This info is not warranted and an engineer needs to do the analysis before you proceed